Efforts to protect ozone layer successful

International efforts to protect the ozone layer-the shield that protects life on Earth from harmful levels of ultraviolet rays-are a success and have stopped additional ozone losses and contributed to mitigating the greenhouse effect, according to a new report.

The "hole" is actually a depletion of ozone concentrations in the stratosphere.

The executive summary of the Scientific Assessment of Ozone Depletion 2010 provides new information about the effects of climate change on the ozone layer, as well as the impact of ozone changes on the Earth’s climate.

The report was written and reviewed by some 300 scientists and launched on the UN International Day for the Preservation of the Ozone Layer. It is the first comprehensive update in four years.

The report reaffirms that the Montreal Protocol is working. “It has protected the stratospheric ozone layer from much higher levels of depletion by phasing out production and consumption of ozone depleting substances.”

Given that many substances that deplete the ozone layer are also potent greenhouse gases, the report says that the Montreal Protocol has “provided substantial co-benefits by reducing climate change.” In 2010, the reduction of ozone depleting substances as a result of the Montreal Protocol, expressed in CO2-equivalent emissions (about 10 Gigatonnes per year), were five times larger than those targeted by the first commitment period (2008-2012) of the Kyoto Protocol, the greenhouse emissions reduction treaty.

The report published by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) says that an important remaining scientific challenge is to project future ozone abundance based on an understanding of the complex linkages between ozone and climate change.

Changes in climate are expected to have an increasing influence on stratospheric ozone in the coming decades, it says. “These changes derive principally from the emissions of long-lived greenhouse gases, mainly carbon dioxide, associated with human activities.”